1. Field of the Invention
This invention relates to the grinding and polishing art and more particularly to an improved combination of motor driven shaft having a particularly configured grinding or polishing disc mounted on the outer end thereof and an exhaust duct or hood in particle removing relationship thereto.
2. Description of the Prior Art
Many forms of grinding and polishing machines and devices have been utilized in the past in a wide variety of applications. And, in general, all such grinding or polishing machines or devices incorporate a rotating grinding or polishing disc against which a work piece that is to be ground or polished is positioned. Some of the machines or devices are fully automated; some are hand held devices; and some utilize a manual positioning of a work piece against the rotating grinding or polishing disc. In general, such grinding or polishing machines in which the work piece was manually positioned against the rotating grinding or polishing disc were characterized in that the generally comprised a housing in which an electrically powered motor was installed. The motor rotated a vertically output shaft and on the remote end of the output shaft there was mounted the grinding or polishing disc. The work piece to be ground or polished was generally placed against the under side of the disc and the grinding or polishing was commenced on the surface of the work piece. As the grinding or polishing continued, dust or particulate matter was generated by the abrasion of the grinding or polishing disc on the work piece. A hood or duct was placed in close relationship to the work piece and the hood or duct had an opening into which the dust or participate matter was conducted to be removed to regions spaced from the grinding or polishing machine. In many applications, a vacuum generating pump or device was connected to the remote end of the duct to aid in the removal of the dust or particulate matter.
Such devices had several disadvantages. Since the work piece was located under the rotating disc to be placed against the underside thereof, the view of the wok piece was often obstructed by the disc. Some prior art discs had a few, narrow radial apertures in regions adjacent the outer periphery of the disc and a small portion of the work piece was visible therethrough during the grinding or polishing operation. However, very often the work piece was removed from engagement with the disc at various times in order to inspect the condition of the work piece and then the work piece was replaced in the grinding or polishing relationship to the underside of the grinding or polishing disc. Further, the exhaust duct or hood was often not located in the position with respect to the work piece to allow efficient removal of the dust or particulate matter.
Accordingly, there has long been a need for a grinding or polishing machine in which more of the surface of the work piece that is being ground or polished may be visible and in which a larger portion of the dust or particulate matter generated during the grinding or polishing operation may be removed.